A166715 - OEIS

A166715

Irregular triangle read by rows: row n lists nonzero quadratic residues modulo the n-th term of A123239.

1, 1, 1, 3, 4, 5, 9, 1, 3, 4, 9, 10, 12, 1, 3, 4, 7, 9, 10, 11, 12, 16, 21, 25, 26, 27, 28, 30, 33, 34, 36, 1, 2, 4, 5, 8, 9, 10, 16, 18, 20, 21, 23, 25, 31, 32, 33, 36, 37, 39, 40, 1, 3, 4, 5, 7, 9, 12, 15, 16, 17, 19, 20, 21, 22, 25, 26, 27

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Quadratic Residue.

EXAMPLE

Triangle starts:

1,3,4,5,9;

1,3,4,9,10,12;

...

Modulo A123239(3)=11, the quadratic residues are 1,3,4,5,9.

MATHEMATICA

MangammalQ[p_]:=Block[{k=3}, While[k>2, k=Mod[3k, p]]; k!=2];

A123239=Select[Prime[Range[17]], MangammalQ];

A166715=Flatten[Union[Mod[Range[Floor[#/2]]^2, #]]&/@A123239] (* Ray Chandler, Jul 21 2011 *)

CROSSREFS

Cf. A046071, A063987, A123239.

Sequence in context: A010375 A095028 A011246 * A330577 A020863 A215496

Adjacent sequences: A166712 A166713 A166714 * A166716 A166717 A166718

KEYWORD

nonn,tabf

AUTHOR

A.K. Devaraj, Oct 20 2009

EXTENSIONS

Edited by N. J. A. Sloane, Oct 22 2009

Edited by Charles R Greathouse IV, Oct 28 2009

Edited, corrected and extended by Ray Chandler, Jul 21 2011

STATUS

approved